Immersion heater



Jan. 13, 1 25- 1,522,992

C. C. ABBOTT IMMERS ION HEATER Filed June 16, 1922 Inventor:

Charles C Abbctt, by 4 His Attorney.

' panying Patented Jan. 13, 1925.

PATENT orrica.

CHARLES C. ABBOTT,

0F PITTSFIELD, MASSACHUSETTS, ASSIGNOR TO GENERAL ELEC- TRIC COMPANY, A CORPORATION OF NEW YORK.

' IMMERSIO'N HEATER.

Application filed June 16, 1922. Serial No. 568,697.

To all whom it may concern.

Be it known that I, CHARLES C. Anno'rr, a citizen of the United Statesyresiding in Pittsfield, in the county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Immersion Heaters, of which the following is a specification.

and has for its object the provision of unprovements in electric immersion heaters. In carrying out my invention 1 use an electric heating unit'o'f the sheath wire" type. In heating units of this type the resistance conductor is embedded in a compacted mass of insulating material enclosed by a metallic sheath. Such units are inherently impervious to moisture, may be readily bent to any desired form and are otherwise adapted for use as an immersion heater. in one form of my invention I mount the sheath wire heating unit on a support adapted to close an opening through which the heating unit is inserted into the receptacle to contain the liquid to be heated. In one embodiment of my invention 1 use a helical core sheath. wire heating unit such as described and claimed in my Patent No. 1,367,341, dated Feb. 1, 1921. In such units the resistance conductor is shaped in the form of a helix whereby a much greater heating effect for a given length of heating unit may be obtained than with the usual straight resistance conductor.

For a better understanding of my invention reference should be had to the accomdrawing in which Fig. 1 is a view partial in section of an electric immersion heater embodying my invention; Fig. 2 is a partial section view of Fig. 1; while Figs. 3 and 4 are modified forms of the electric heater shown in Fig. 1.

Referring to Figs. 1 and 2 of the drawing,

- in one form'of my invention the sheath wire heating unit 10 is bent on itself or doubled over in the shape of ahair in and has its ends secured to and exten ing through a screw plug 11. The heating unit is of the helical core sheath wire type, such as described and claimed in n Patent No. 1,367 an. The resistance con actor 12. is she ed inthe form of a helix and is embedde in heat refractory insulating material 18 com- My invention relates to immersion heaterspactcd to a hard dense mass within the metallic enclosing sheath 14. As described in my aforesaid patent, the sheath 14 is formed from a length of tubing, the insulating material being compacted by reducing the diameter of the sheath by swaging. The heating unit is therefore throughout its length completely impervious to moisture.

The plug 11 may be a standard pipe plug. having threads 15 adapted to fit in any standard tapped opening of a corresponding diameter.

The heating element 10 is provided with terminal lugs 16 and 17, such as described and claimed in my Patent No. 1,494,938 dated May 20, 1924. in assembling the heating unit to the plug 11 the ends of the heating unit, preferably before the terminal lugs 16 and 17 are attached, are inserted through parallel bores 18 and 19 .in the plug. The ends are inserted through the bores in such direction that they project from the outer end of the plug. The terminal lugs 16 and 17 are secured in place, for example, by swaging as described in my aforesaid patent, and seated tightly on insulating washers 18' and 19' so as to seal the ends of the heating unit against the entrance of moisture. Either before or after the terminal lugs are applied, the plug is moved to its proper position near the ends of the heating unit and secured by making brazed or soldered joints 20 and 21. As shown in the drawing, the plug is secured closely adjacent the insulating washers 18' and 19'. The plug is provided with a short rim 22 over which fits a protecting cap 23 for the terminals. This cap is provided with a central aperture 24 through which the electrically conducting leads (not shown) connected to the terminals may extend.

As thus constructed the electric heater is adapted to be applied to the' receptacle in which the liquid is to be heated by inserting the heating unit 10 through a suitable tapped opening in the receptacle and then screwing the plug tightly in the tapped opening so as to make a leak-proof connection. The heating unit 10 thus extends within the receptacle in position to be immersed in the liquid to be heated. It will be observed that this arrangement of the sealing the containing vessel.

heating unit provides for convenience both in putting the electric heater in place and in The heater may also be easily removedeat any time for repairs or replacements.

In the modification shown in Fig. 3 the heating unit 10 is twisted inthe form of a double helix. This form provides for the concentration of the heating effect into a much smaller space. In the modification shown in Fig. 4:, two heating units 10 are mounted on a single plug. These heating elements are preferably provided'with sepa' rate terminals and connections'whereby. they may be connected in series or parallel relation in a well-known manner so as to regulate the amount of heat produced. Obviously, various otherarrangements and configurations of the heating unit may be'used.

While I have described my invention as embodied in concrete form. and as operating in a specific manner in accordance with the provisions of the patent statutes, it should be understood that I do not limit my invention thereto, since-various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of m invention, thesco e of which is set fort in the annexed clalms.

What I claim as new and desire to secure by Letters Patent of the United States, is

1. An electric immersion heater comprising a metallic support adapted to close an" aperture in a containing receptacle, a metallic sheath soldered to said support so as to form a water-tight connection therewith,

a resistance conductor in said sheath, and

powdered heat refractory insulating mate-- rial compacted in said sheath around said resistance conductor so as to freely conduct heat from said resistance conductor to said sheath.

2. An electric immersion heater comprising a metallic screw plug provided with apertures, a metallic sheath bent on itself and having its ends extending through said.

CHARLES C. ABBOTT. 

